The present invention relates to an image sensing device for obtaining color image signals, an image sensing apparatus and an image sensing system using the image sensing device, an image processing method, and a computer readable storage medium storing program codes of the image processing method.
Conventionally, there is an image sensing apparatus which acquires image signals (color image signals) of an object using an image sensing device, covered with a color filter, on which an optical image of the object is formed, applies image processes, such as compression and expansion, to the acquired image signals, and displays the processed image signals and/or records the processed image signals in a storage medium.
In compression processing performed in such an image processing apparatus, image signals outputted from the image sensing device are divided into blocks of a predetermined size, applied with, e.g., discrete cosine transformation, quantization, and/or variable length coding by blocks, and compressed data is obtained.
As processes to be performed in advance of image processes, such as compression, (referred to as xe2x80x9cpre-processingxe2x80x9d hereinafter) signals output from the image sensing device (specifically, if color filters covering the image sensing device are complementary color filters, the output signals are Ye (yellow), Cy (cyan), Mg (magenta) and Gr (green) raw signals, and if they are primary color filters, the output signals are R (red), G (green) and B (blue) raw signals) are temporarily stored in frame memory or line memory, applied with color processes, such as white balance correction and xcex3 correction, then a luminance signal Y and color difference signals U and V are obtained on the basis of the processed signals. Then, the aforesaid image processes, such as compression, are applied to the luminance signal Y and the color difference signals U and V obtained as a result of the pre-processing.
Further, as another example of the image processes, besides compression, performed after the pre-processing, there is a process for determining whether or not a given color is a complexion (complexion recognition) for discriminating a human in an image.
FIG. 22 is a block diagram illustrating a brief configuration of a conventional image sensing apparatus capable of performing the complexion recognition. As shown in FIG. 22, the image sensing apparatus converts analog image signals outputted from a CCD (image sensor) 101 into digital signals in an analog-digital (A/D) converter 102, and stores a predetermined amount of digital signals (e.g., data of two lines) in line memory 103.
Thereafter, the image data stored in the line memory 103 is applied with color processes, such as white balance correction and xcex3 correction, by blocks of, e.g., 2xc3x972 pixels in a color processing circuit 104, and a luminance signal Y and color difference signals U and V are generated. Then, the color difference signals U and V are provided to a complexion determination circuit 105, where whether a color, expressed by the color difference signals U and V, is a complexion or not is determined on the basis of the color difference signals U and V.
In the aforesaid conventional image sensing apparatus, image signals are serially outputted; therefore, the frame memory or line memory for the pre-processing is necessary. Further, time for waiting until image signals necessary for pre-processing are stored in the frame memory or line memory is required. Furthermore, considerably large number of operations are to be performed in the pre-processing, which has limited to increase throughput.
Thus, the image processes, such as compression and complexion determination, which are subsequent processes to the pre-processing are not performed efficiently in the conventional image sensing apparatus.
The present invention has been made in consideration of the above situation, and has as its object to provide an image sensing device capable of performing high precision image processes efficiently.
According to the present invention, the image sensing device comprises a sensor unit having a plurality of pixels; control means for controlling to read signals from the sensor unit by pixel blocks of a predetermined size; and signal processing means for acquiring luminance and color difference information on the basis of the signals, read from the sensor unit, by pixel blocks of the predetermined size.
It is another object of the present invention to provide an image sensing device capable of performing color determination processing for a given pixel.
According to the present invention, the image sensing device further comprises color determination means for determining whether or not the color difference information acquired by the signal processing means represents predetermined color.
Further, it is still another object of the present invention to provide an image sensing apparatus and an image sensing system using either of the aforesaid image sensing devices, an image processing method, and a computer readable storage medium storing program codes of the image processing method.
According to the present invention, the image sensing apparatus includes a sensor unit having a plurality of pixels; control means for controlling to read signals from the sensor unit by pixel blocks of a predetermined size; signal processing means for acquiring luminance and color difference information on the basis of the signals, read from the sensor unit, by pixel blocks of the predetermined size; and compression means for compressing the luminance and color difference information calculated by the signal processing means.
According to the present invention, the image processing method comprises a reading step of reading signals of a plurality of pixels by pixel blocks of a predetermined size; and a signal processing step of acquiring luminance and color difference information on the basis of the signals read by pixel blocks of the predetermined size in the reading step.
According to the present invention, the computer readable storage medium includes program codes of the steps of either of the aforesaid image processing methods.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.